1. Field of the Invention
This invention is concerned with tools for swaging fastener collars onto fastener pins to rigidly fasten panels or wall structures together. A coupling for adapting a non-rotatable nose assembly tool for rotatable operation can be used between a conventional offset nose assembly and a conventional installation tool to provide the nose assembly with a rotary adjustment capability.
2. Description of Prior Developments
Lockbolt fastener installation tools are typically fitted with a fastener-engaging nosepiece which is actuated by a piston driven through a double-acting hydraulic cylinder. The nosepiece commonly includes an anvil body attachable to the tool cylinder, and a collet and jaw assembly attachable to the tool piston.
During operation of the tool, an axial motion of the piston causes the anvil to react axially so as to swage a fastener collar onto a fastener pin which is axially pulled by the collet and jaw assembly. In some applications the fasteners are located behind structures that obstruct the area along the fastener pin axis. To meet requirements imposed by such obstructed access installations there have been devised various "offset" nose assemblies.
Offset nose assemblies locate the collet and jaw assembly in an offset position spaced radially away from the tool cylinder axis. The offset nose assembly can thus be extended laterally into otherwise obstructed spaces for swaging pin and collar fasteners that would otherwise be inaccessible with conventional in-line nose assemblies.
A nose assembly of the offset type is shown in U.S. Pat. No. 4,796,455. The tool and nose assembly are rigidly and non-rotatably attached so that when the tool is held in a position most comfortable for the operator, the nose assembly may not in all instances be correctly aligned for setting the fastener. The human operator may be required to assume awkward and uncomfortable positions in order to manipulate the tool to correctly access and set the fasteners. Because installation tools can weigh from 8 to 15 pounds, an operator can quickly experience muscle fatigue. This fatigue can result in lower production rates.
To overcome the deficiencies of conventional offset nose assemblies, U.S. Pat. No. 4,813,261, provides a design for a nose assembly that can be rotatably adjusted to different positions. The construction is specially designed to be rigidly attached to a tool with a threaded adaptor coupling and smooth-surfaced sleeve. Relatively close manufacturing tolerances are maintained on the interfitting surfaces between the nose assembly and the tool to prevent deflection of the nose assembly during swaging.
U.S. Pat. No. 4,813,261 requires a threaded coupling to be rigidly affixed to a drawbar that extends through a collet. The drawbar is designed to be threaded onto a piston that forms part of the installation tool. The piston and drawbar are thus rigidly coupled together to form an elongated non-rotary support system for the rotary collet. While this nose assembly functions quite well, a need exists for adapting conventional non-rotatable nose assemblies for rotation about the piston axis of an installation tool.